It is an important subject for producing agricultral products by accelerating the growth of agricultural plants to increase the yield per unit area and further to increase the cultivating number of times. As growth accelerating materials for plants, plant hormones such as gibberellin and auxin are reported, but such a plant hormone gives various actions on plants; that is, some actions of the plant hormone are useful for the plant but other actions are, sometimes, harmful for the plant, and hence the practical use of such a plant hormone is limited to a specific case.
On the other hand, recently it has been reported that an oligosaccharide obtained by the decomposition of a polysaccharide. constituting the cell walls of plant has an important role as a material for controlling the plant host defence and the differentiation of the plant itself.
For example, it is reported that oligogalacturonic acid, when applied to soybean, has an action of accelerating the synthesis of a certain kind of antibacterial material (Phyloalexin) to increase the resistance of the soybean to disease germs and also an oligosaccharide (xyloglucan) prepared from the cell wall of a maple tree has an effect of, on the contrary, restraining the growth acceleration action of auxin to the seedlings of peas.
As described above, the action of an oligosaccharide is rather different from a plant hormone.